The present invention relates to an ink jet recording device and a method of producing the same and, more particularly, to a multinozzle ink jet recording device having a dense arrangement and applicable to a printer, facsimile, copier or similar image forming apparatus, and a method of producing the same.
Ink jet recording devices for the above application are generally classified into two types, a thermal ink jet or bubble jet type and a piezoelectric type with respect to a drive source for ink ejection. A thermal ink jet or bubble jet type device is taught in, e.g., Japanese Patent Publication No. 61-59913. This type of device includes a thermal head having a plurality of thermal elements arranged thereon. Pressure chambers are each associated with the respective thermal element. Nozzles and ink passages are communicated to the pressure chambers. In operation, power is selectively applied to the thermal elements so as to heat ink existing thereon, thereby producing bubbles. As a result, the ink is ejected via the nozzles by the pressure of the bubbles.
The above thermal head or drive source implements a dense multinozzle print heat because it can be fabricated by photolithography. An ink jet recording device with such a print head is miniature and operable at a high speed. However, the problem with this type of device is that the ink must be heated to above 300.degree. C. for producing bubbles. When the ink is ejected over a long period of time, the components of the ink deposit on the thermal elements and bring about defective ejection. Moreover, it is likely that the print head is damaged by thermal stress and cavitation or effected by passivation ascribable to pinholes existing in the protection layer of the thermal elements. For the above reasons, it i s difficult to provide the print head with a long service life.
A piezoelectric type ink jet recording device is disclosed in, e.g., Japanese Patent Publication No. 53-12138 and includes pressure chambers communicated to nozzles and ink passages. Piezoelectric elements cause the volumes of the pressure chambers to vary. In operation, a voltage is selectively applied to the piezoelectric elements so as to cause the volumes of the pressure chambers to vary. As a result, ink drops are ejected from the pressure chambers. This type of device is operable with a broad range of ink and has a long life. However, the problem is that it is difficult to arrange a number of piezoelectric elements in a dense configuration, making it difficult to implement a miniature high-speed ink jet recording device.
Japanese Patent Laid-Open Publication Nos. 62-56150, 63-252750 and 5-338147 each proposes an ink jet recording device for solving the above problem. However, none of the proposals can solve problems which will be described later.